1. Field of the Invention
The present invention relates to a device, method and system for enhancing optical properties of a camera system of a mobile terminal device. Particularly, the invention relates to a device, method and system for enhancing optics of a mobile terminal device having a variable camera system employing a cover that integrates variable lenses.
2. Description of the Prior Art
The second generation mobile phone systems, such as GSM, have significantly increased over the last years. The penetration of mobile phones exceeds 80% in countries with advanced wireless markets. The second generation mobile communication systems are optimized for voice traffic. The coming third generation mobile communication system enables not only the intermediate standards of the second generation mobile communication system but also the handling of high data rate services and will provide for voice traffic as an additional service. Wireless communication will be extended to further services which are limited by the low data rate of the second generation mobile communication systems.
One of the services requiring high data rates will be the possibility to transmit and receive high quality images and videos. The capability of high data rates allows providing this service within acceptable transmission duration and acceptable costs.
Therefore, coming mobile phones will include digital cameras to take pictures which may be transmitted to other participants of the mobile communication system, like friends or colleagues or suitable recipients connected in any way to the mobile communication system. For example, a built-in digital camera will provide the possibility to operate video telephony. The number of applications using built-in digital cameras and also camera modules plugged into a mobile phone are numerous and the possibility of transmitting pictures will improve the performance of communication in an advantageous way. The success of messages according to the short message service (SMS) standard which enables the transmission of simple low resolution pictures may give a hint to the coming success of video and picture transmission with high resolution.
A digital camera built within a mobile phone or provided as an external digital camera module plugged into a mobile phone will fulfil its function although several restrictions have to be imposed on the digital cameras, such as size, weight, power consumption, and the like. Small mobile sized phones of low weight fulfil the demands of the market and the consumer. Accordingly, additional built-in equipment or plugged-on equipment will have to fulfil the same demands to be acceptable by the users.
Preferably, CMOS sensors are used as detector system for digital cameras. The size of charged coupled devices (CCD) allows designing digital cameras of small size and low weight. According to size and weight of mobile devices, the optics of the digital camera system have to be subject to the same restrictions. That means that advanced optics known from prior stand-alone digital cameras can not be used for digital cameras built into mobile terminals. Size and weight of advanced optics will exceed the restrictions. Therefore, the digital cameras are equipped with fixed focus imaging optics which limits the distance for sharp imaging to a imaging distance resulting from the design of the fixed focus imaging optics. Often the imaging is limited from about 50 cm to infinity. Moreover the (horizontal as well as also vertical) field of view is fixed to a pre-defined value.